1. Field of the Invention
The present invention relates to a transmission system comprising at least two transmitter channels for connecting a transmitter and a receiver.
2. Description of the Prior Art
Systems of this type provide on the side of the transmitter:
means for transmitting transmit data by at least two channels, and on the side of the receiver: PA1 a first deserializing circuit for producing N-bit words based on received data, PA1 a permutation circuit for producing permuted words by permuting the bits of the N-bit words as a function of said shift information, PA1 a plurality of second deserializing circuits for connecting each of the N outputs of the permutation circuit in parallel to M outputs by taking from the buffers the data as a function of the shift information.
receiving circuits for receiving the data coming from the channels, PA2 a coincidence providing circuit for the data coming from said channels, formed by: PA2 a switching circuit for connecting a user circuit to one of said channels.
a detection circuit for detecting the shift between the data coming from the channels, to produce shift information, PA3 a shifting circuit for shifting the data of at least one of said channels as a function of said shift information,
The invention likewise relates to a receiver suitable for such a system.
Systems of this type find important applications in the field of digital data transmission by radio waves or others. This type of system includes means for remedying failures of a transmitter channel. These means are formed by the presence of a help channel. The problem then posed is the passing through this help channel and the return to the normal channel. These channel changes are to be effected without the user noticing what it is, thus without data loss. This is called hitless. This should only happen if the data coming from the two channels coincide binary digit by binary digit (bit by bit).
A system of this type is described in European Patent Application no. 0 137 563. Although this system gives complete satisfaction, it has been established that this system is unsuitable, one the one hand, when the data coming from these channels present a shift that is more than several bits and, on the other hand, was unsuitable for processing data at a high rate.